The invention is an improved separator disc for use in mechanical separation of grain and grain-like particles according to particle length. It is particularly useful in separating cereal grains, rice, seeds and other grain-like particles that are mixed or comingled so that, for example, rice grains are separated from oats.
The invention is in the field of separation by a series of spaced parallel discs rotating on a common shaft. The discs are formed with pockets in the exposed plane surfaces. Approximately the lower third of each disc is submerged in and rotates through the grain or seed mixture. Shorter grains are lodged in the pockets in the disc and are lifted from the mixture or pool of mixed grain and are dumped above the mixture as the disc rotates, to separate grains and/or grain-like particles all in the conventional manner.
For more than seventy years disc separators have been constructed with one-piece separator discs made from cast iron. Such discs are shown and described in early U.S. patents issued to the predecessor-in-interest of the assignee of the present application, namely, Carter U.S. Pat. No. (1,364,247) and Carter U.S. Pat. No. (1,437,042). The disc separators shown in these patents, as well as those shown and described in other prior art patents, such as Kehlor U.S. Pat. No. (415,275), Miller U.S. Pat. No. (1,390,806) and Dempsey U.S. Pat. No. (2,707,554), are characterized by a series of one-piece, cast-iron discs mounted in spaced parallel relationship for rotation on a common shaft.
The cast iron construction makes the discs extremely heavy, makes the casting process somewhat complicated, and results in discs that are subject to wear, which requires periodic replacement of worn discs. When a worn disc is replaced, the one-piece construction of the discs requires that the worn disc be moved axially along the shaft and the new replacement disc moved axially along the shaft in the opposite direction into its proper position. This requires removal of each disc between the worn one and the end of the shaft. In the case of the innermost discs on the shaft as many as 30 discs might have to be removed to allow removal and replacement of the worn disc. This is a substantial amount of work. In addition to removal of unworn discs, the shaft must also be removed from its bearings or mounting brackets to allow the worn disc to pass beyond the end of the shaft and be removed. These disadvantages have existed, have been recognized, and have gone without solution for seventy years.
The Williams U.S. Pat. No. (4,795,036) teaches a split cast-iron disc in the context of a rotary disc screen conveyor apparatus, and teaches removal and replacement of the discs with different size discs for screening and conveying different sized objects, but does not teach use of the split-ring design in a disc separator for separation of grain and grain-like particles according to particle lengths, nor does Williams teach the light weight separator disc of the present invention.
The present invention fulfills the long-felt need for elimination of the disadvantages associated with the one-piece, cast iron separator disc. It results in a much lighter disc that can be molded more cheaply, provides for less wear, less plugging, and provides for dissipation of static electricity (like the cast iron discs). In addition it can be removed individually from the shaft in a direction transverse to the axis of the shaft without the need to remove other discs on the shaft.